[PATCH 1/3] fanotify: only destroy mark when both mask and ignored_mask are cleared

[Lino Sanfilippo]

In fanotify_mark_remove_from_mask() a mark is destroyed if only one of both
bitmasks (mask or ignored_mask) of a mark is cleared. However the other mask
may still be set and contain information that should not be lost. Thus only
destroy a mark if both masks are cleared.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@xxxxxx>
---
 fs/notify/fanotify/fanotify_user.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index c991616..03a0dd1 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -488,6 +488,8 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 					    int *destroy)
 {
 	__u32 oldmask;
+	__u32 new_mask;
+	__u32 new_ignored;
 
 	spin_lock(&fsn_mark->lock);
 	if (!(flags & FAN_MARK_IGNORED_MASK)) {
@@ -497,9 +499,11 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 		oldmask = fsn_mark->ignored_mask;
 		fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask));
 	}
+	new_mask = fsn_mark->mask;
+	new_ignored = fsn_mark->ignored_mask;
 	spin_unlock(&fsn_mark->lock);
 
-	*destroy = !(oldmask & ~mask);
+	*destroy = !(new_mask | new_ignored);
 
 	return mask & oldmask;
 }
-- 
1.9.1

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